A state-of-the-art instrument is being sought for shared-use, primarily by the major user group with active ongoing biomedical research programs. The instrument is an electron microscope capable of operation either in the high resolution scanning or transmission modes. The instrument will replace an obsolete instrument and will substantially benefit present and future research activities by providing an instrument that is unavailable or to which availability is highly limited. The studies of the major users involve surface events in gamete formation and function, stereological analysis of hepatocytes and cells of the pulmonary parenchyma, and of skin from normal, diseased and mutant adults and fetuses. The instrument will contribute not only to these research programs, but to those of collaborators and other potential users in the institution. It will complement other research approaches of common use in contempprary cell biology and contribute to research capabilities to research capabilities of the overall research community at this institution.